Bicycle transmission

ABSTRACT

This invention relates to multi-speed bicycle transmissions and more particularly to an improved, pedal hub located and drive pedal responsive multi-speed bicycle transmission system.

BACKGROUND

Although bicycles have been widely used for a long period of time,recent years have witnessed a widespread increase in the popularity ofbicycling as a healthful and enjoyable recreational activity, as well asa renewed awareness of their utility as an inexpensive means ofindividualized local transportation. As a concommitant thereto, therehas been a renewed emphasis on the utilization of multi-speedtransmission systems for bicycles to enhance their operationalefficiency over various types of terrain and to accommodate the everexpanding differences in the state of physical conditioning andcapabilities of the users thereof. Although the patented art is repletewith many different types of suggested multi-speed transmission systems,economic realities and practical considerations have apparently limitedwidespread commercial usage to two, three and five speed transmissionslocated within the rear wheel hub and to the widely utilized ten speedtransmissions of the "derailleur" type, all of which are normallyoperable in response to a cable connected and manually manipulatableshift lever and which require a hand operated brake system. Also used,but to a lesser extent, are the more complicated drive pedalmanipulative types of rear wheel hub multi-speed transmissions that arecompatible with coaster brake drive systems, as for example, the Fichteland Sachs AG "Torpedo" transmissions.

Among the many suggested bicycle transmission systems disclosed in thepatented art are numerous disclosures of coaster brake compatible, rearwheel hub transmissions activated by reverse drive pedal rotation, asexemplified by the patents of Schwerdhofer (for example--U.S. Pat. Nos.3,648,809, 3,270,589, 3,200,699, 3,180,181, 3,147,641); Hood (forexample--U.S. Pat. Nos. 3,022,682, 2,993,575, 2,982,384, 3,972,908,2,940,339) and Gleasman (for example--U.S. Pat. Nos. 3,354,750,2,993,389, 2,903,913, 2,914,152). Other suggested and exemplaryexpedients for rear wheel hub transmission systems include reverse drivepedal actuatable epicyclic gear systems as disclosed in U.S. Pat. Nos.3,351,165, 3,433,097, 3,803,947 and 3,726,156 and manually selectablerear wheel hub transmissions as embodied in U.S. Pat. Nos. 3,653,273 and3,886,811.

Rear wheel hub multi-speed transmission systems, and particularly thosethat are coaster brake compatible, are of relatively complicatedconstruction with diminutively sized components dictated by the limitedavailable space. As such and because of the wheel diameter lever arminherent in rear wheel hub located multi-speed transmissions, such areunduly subject to damage through normal, much less abusive, use and therepair thereof is usually both relatively difficult and expensive. Eventhe simpler rear wheel hub multi-speed transmission systems that arewidely employed in hand brakeable bicycles, such as the Sturmey-Archerthree speed and "derailleur" type multi-speed transmissions, are subjectto hub component and gear shift cable damage that necessitate relativelyexpensive repairs as well as requiring diversion of the rider'sattention when manual shifting is to be effected.

Early expedients for proposed utilization of the drive pedal hub area asa situs for multi-speed transmission components for bicycles areillustrated in U.S. Pat. Nos. 2,047,174 and 2,165,201 and in SwissPatent No. 183,921. In each of these patents an in-line type ofmulti-speed transmission is employed, apparently sized to be containedwithin the drive pedal hub. Selective gear engagement was thereineffected by spring biased radial pawl displacement induced by a controlcam element disposed within an axial bore within the drive pedal shaftand operable in response to reverse rotation of the pedal drive shaft.Such approach is also characterized by diminutively sized componentsunduly subject to damage in a high stress location.

Recent years have witnessed a refocussing of attention upon the drivepedal hub as a suitable situs for multispeed transmission components forbicycles. One suggested expedient includes the utilization of aplanetary gear system adjacent to the drive pedal hub that is compatiblewith a rear wheel hub coaster brake assembly but which requires manualoperation of an external gear shift lever to effect shifting. Such asuggested construction is disclosed in the Shea U.S. Pat. Nos.3,727,484, 3,766,805 and 3,842,691. Other suggested expedients includeimpact responsive shifting mechanisms, and manually controllablevariations in the main drive pedal sprocket diameter. Illustrative ofsuch expedients are U.S. Pat. Nos. 2,600,586, 1,608,141 and 3,506,100and various publications such as Design News of Dec. 16, 1974 (pp. 46-7)and Product Engineering of June 1973 (p. 13).

BRIEF SUMMARY OF THE INVENTION

This invention may be briefly described as an improved multi-speedbicycle transmission located at the drive pedal hub and uniformlyoperable in response to a limited degree of simple pedal manipulationunder all conditions of cycle operation from zero to maximum attainablespeed. In its broader aspects, the subject invention includes animproved self-contained, drive pedal hub located, in-line typemulti-speed transmission wherein a plurality of change speed drive gearsare journalled on the pedal drive shaft and are in constant runningengagement with corresponding companion spur gears and wherein a drivepedal responsive shifting mechanism disposed within the drive pedal hubselectively couples individual change speed drive gears in drivingengagement to the pedal drive shaft to provide a plurality ofpreselectable and different transmission ratios for the main pedal drivesprocket. In its narrower aspects, the subject invention includes apedal hub located transmission of the in-line type wherein selectivedriving engagement of individual drive gears is effected, in the absenceof driving stresses, by limited reverse rotation of the pedal driveshaft at a pair of preselected locations in the normal path of rotativedisplacement thereof and wherein the driving interconnections betweenthe drive gears and the drive shaft is effected by members subjectedonly to compressive stress under drive conditions. In a still furtheraspect, the subject invention includes an improved shifting mechanismassembly for multi-speed in-line type of transmissions wherein thedriving interconnection between the drive gears and the drive shaft iseffected by members subject only to compressive stresses under drivingconditions.

Among the manifold advantages of the subject invention is the provisionof an improved multi-speed bicycle transmission that may be used alonewith hand brakeable bicycles in accord with the desires and dictates ofthe rider and which may be compatibly employed in association withcertain existing hand brakeable, gear shift operated and coaster brakeincompatible multi-speed rear wheel hub transmissions, such as thewidely employed Sturmey-Archer three speed transmissions, toconveniently provide an expanded number of available transmissionratios. Further advantages include the provision of an in-linetransmission located at the drive pedal hub, wherein the stressmagnitudes on the shifting and drive components are relatively small,wherein the gears may be preselected to provide any desired gear ratiosand which gears may be readily interchanged to modify the gear ratioswhenever required. Another advantage includes the general provision ofan in-line multi-speed transmission wherein the critically stresseddrive system components, such as the interconnection of the drive gearswith the drive shaft, are subjected only to compressive stresses whendrivingly engaged. Other advantages include the provision of a factoryassembled and sealed in-line type of multi-speed transmission of ruggedand durable character for bicycles that affords a long operating lifeand singular freedom from maintenance and repair. Further advantagesinclude the provision of a drive pedal actuatable gear shiftingmechanism that dispenses with control cables, that does not require therider to remove his hands from the handle bars or divert his attentionfrom the path of bicycle travel during the shifting operation and whichis operable by simple, facile and rapid drive pedal manipulation withinlimited arcs of reverse pedal displacement at readily locatablepositions in their path of rotation, all to the end of readilypermitting rapid gear shifting in times of emergency or the like. Stillother advantages include the provision of an improved multi-speedbicycle transmission of the in-line type where shifting can be effectedindependent of the speed of the bicycle, including while at rest,wherein all components are automatically disposed in an effectivelystress free condition when shifting is being effected and wherein oneset of gears, even during the shifting operation, is always drivinglyengaged. A still further advantage is the permitted avoidance of allhand manipulative operations for shifting purposes, which not onlypermits continued manual control of steering and braking at all timesbut which also dispenses with any necessity for visual diversion fromthe path of travel with increased safety for the bicycle rider. Stillfurther advantages of the subject invention include the provision of areliable and economic in-line type of multi-speed transmission forbicycles that is effectively immune to damage arising from any pedalmanipulation.

The primary object of this invention is the provision of an improvedmutli-speed transmission for bicycles.

Another primary object of this invention is the provision of a pedal hublocatable and drive pedal actuatable multi-speed bicycle transmission ofimproved character.

Another object of this invention is the provision of a pedal hub locatedand drive pedal operable multi-speed bicycle transmission whereinshifting is effected by selective pedal manipulation in accord with thedictates and desires of the rider.

Still another primary object of the invention is the provision of animproved in-line multi-speed transmission construction wherein thedriving interconnection between the drive gears and the drive shaft iseffected by members subjected only to compressive stress under driveconditions.

A still further object of this invention is the provision of an improvedpedal hub located and drive pedal actuatable multi-speed bicycletransmission that can be used alone in hand brakeable bicycles or inassociation with coaster brake incompatible rear wheel hub transmissionsto inexpensively provide an expanded number of available gear ratios.

Other objects and advantages of the subject invention will becomeapparent from the following portions of this specification and from theappended drawings which illustrate, in accord with the mandate of thepatent statutes, a presently preferred drive pedal operable multi-speedbicycle transmission construction incorporating the principles of thisinvention.

DESCRIPTION OF APPENDED DRAWINGS

Referring to the drawings:

FIG. 1 is a schematic side elevational view of a bicycle constructed inaccord with the principles of this invention;

FIG. 2 is a schematic oblique view, partially cut away and sectioned, ofa pedal hub located and drive pedal actuatable multi-speed bicycletransmission constructed in accord with the principles of thisinvention; and including, for the purposes of convenience and clarity ofillustration and explanation, certain components that are rotationallydisplaced from the normal location thereof as shown in FIG. 3;

FIG. 3 is a horizontal section through the pedal hub located multi-speedbicycle transmission constructed in accord with the principles of thisinvention; and as taken on the line 3--3 of FIG. 4;

FIG. 4 is a section as taken on the line 4--4 of FIG. 3;

FIG. 5 is a section as taken on the line 5--5 of FIG. 3;

FIG. 6 is a schematic sectional view as taken on the line 6--6 of FIG.5;

FIGS. 7A and 7B are enlarged partial sections as would be taken on theline 7--7 of FIG. 2 to illustrate the driving interconnection of thepedal shaft with the drive gears;

FIGS. 8A and 8B are plan and vertical sectional views respectively ofthe pawl members that provide the driving interconnection between thepedal drive shaft and the drive gears;

FIG. 9 is an oblique view of the pivotally mounted shift control member;

FIGS. 10A and 10B are schematic sectional views, similar to FIG. 5,generally illustrative of operative interengagement of camming ridgeswith the pin members during pedal shaft rotation;

FIGS. 11A through 11D are schematic unfolded plan views of the collarsurface, camming ridges thereon and the pin members on the pivotallymounted shift control member and are illustrative of the operativeinterengagement of the camming ridges with the pin members duringshifting operations in response to pedal shaft displacement.

DETAILED DESCRIPTION OF INVENTION

Referring to the drawings and initially to FIG. 1, there is provided abicycle having a front steerable wheel 10 and a rear driving wheel 12mounted on a frame, generally designated 14. The frame 14 is ofconventional tubular construction and generally includes a substantiallyvertical seat post member 16, a horizontal upper member 18, an angularlydisposed lower member 20, a bifurcated front wheel support 22, abifurcated rear wheel support 24 and a pair of rearwardly extendinglower members 26. The seat post member 16, lower member 20 andrearwardly extending lower members 26 commonly terminate at a transversecylindrical pedal drive shaft hub, generally designated 30, which, aswill hereinafter be described, forms a portion of the housing for theimproved multi-speed transmission system incorporating the principles ofthis invention. For introductory explanatory purposes, however, suchbicycle also includes a transversely disposed drive pedal shaft 32journalled in the hub 30 having conventional opposed right and leftpedal cranks 34 and 36 terminally mounted thereon. Rotatably mounted atthe terminal ends of the cranks 34 and 36 are independently rotatabledrive pedals 38 and 40 respectively. For clarity of description herein,the terms "right" and "left" will accord with the right and left sidesof the bicycle rider as he would normally use the bicycle. The rear ordrive wheel 12 includes a hub 46 and sprocket 48 drivingly connected bya chain 50 to the main drive sprocket 52 mounted on the right side ofhub 30. The sprocket 52 is positively driven, through the hereinafterdescribed transmission, by rotation of the pedal cranks 34 and 36 in theclockwise direction as viewed from the right. Hand levers 54 are mountedon the handle bars for actuation of conventional wheel rim brake pads.

Referring now to FIGS. 2 through 4, and from which the right and leftpedal cranks 34, 36 and pedals 38, 40 have been omitted for drawingclarity, there is provided a generally rectangular gear housing 62disposed between the main drive sprocket 52 and the right hand terminalend 32 R of the drive pedal shaft 32. The gear housing 62 may bepositioned by a U shaped bracket 60 engaging one of the rearwardlyextending lower members 26 and is conveniently formed of casing halves64 and 66 secured together by screws 68. Disposed within the gearhousing 62 is a multi-element in-line transmission of the general typedisclosed in U.S. Pat. No. 3,812,735. The specifically illustratedtransmission is a three speed transmission and, as will be apparent tothose skilled in the art, any speed multiple can be accommodated withinthe orbit of the disclosed invention.

More specifically, however, the casing halves 64 and 66 are internallyshaped to provide a pair of inwardly directed stub axles 70, 72 thatsupport a stationary bearing sleeve 74. Rotatably mounted on thestationary bearing sleeve 74 is a freely rotatable bearing sleeve 76having secured thereto the cylindrical hub 78 of a first spur changegear 80. Mounted on the hub 78 of the first spur change gear 80 andsplined thereto, as at 82, for concurrent rotation therewith are anydesired number of additional spur change gears, as for example, thesecond and third spur change gears 84 and 86 for the illustrated threespeed transmission. As will now be apparent, the three spur change gears80, 84 and 86 and the bearing sleeve 76 are journalled for free butconcurrent rotation about the stationary bearing sleeve 74.

Disposed in constant running meshed engagement with the three spurchange gears 80, 84 and 86 respectively are three drive gears 92, 94 and96. The drive gears 92, 94 and 96 are journalled for independent andindividually free rotation about a diametrically enlarged hub portion106 of the pedal drive shaft 32 and, as will be described hereinafter,are adapted to be disposed in individual selected driving engagementtherewith. The innermost drive gear 92 is shaped to include an axiallyextending cylindrical flange or skirt portion 100 that is sized toextend through a suitable bore 102 in the left casing half 64 and hasthe main drive sprocket 52 mounted in keyed engagement thereon forrotation in conjunction therewith.

The bores 128 of the drive gears 92, 94 and 96 are sized to be rotatablysupported by the enlarged hub portion 106 of the pedal drive shaft 32and each such bore 128 includes a plurality of generally rectangularpawl engageable recesses 108 therein. As shown in FIGS. 2-4 and as alsoshown in enlarged form in FIGS. 7A and 7B, the enlarged hub portion 106of the pedal drive shaft 32 includes an elongate longitudinal pawlcontaining outer recess 110 overlying the outwardly facing end of aninner and smaller elongate longitudinal channel 112 sized to extendalong the pedal drive shaft 32 and adapted to contain therewithin anelongate displaceable leaf spring type actuating member 114. Disposed atthe terminal end of the elongate leaf spring type actuating member 114operatively related to the drive gears 92, 94 and 96 is an angularlyshaped cam surface 124 that is normally biased radially outwardly fromthe axis of the pedal shaft 32 and upwardly toward and into the outerrecess 110. Disposed within the outer longitudinal recess 110 are aplurality of discrete and selectively shaped drive pawl members 116, onefor each of the drive gears 92, 94 and 96. Each of the pawl members 116is normally biased downwardly within the recess 110 and out of drivingengagement with the respective pawl engageable recesses 108 in the bores128 of the drive gears 92, 94 and 96 by the action of the ring typebiasing springs 118 contained within the circumferential recesses 120 inthe enlarged hub portion 106.

The pawl members 116 are all of similar configuration and comprise agenerally rectangularly shaped block of metal of high compressivestrength. As best shown in FIGS. 8A and 8B, and to a lesser extent inFIGS. 4, 7A and 7B, each pawl 116 includes a front portion 126 having aflat undersurface 250 sized to rest upon and be supported by theshoulder 252 forming the bottom of the recess 110. The front wallportion 254 includes a recess 256 and an inclined wall 130. The uppersurface of the front of the pawl includes two oppositely inclinedsurfaces 258 and 260 having a crest 262 at their apex. Disposed at therear of the inclined surface 260 is a transverse slot or recess 264having a spring wire receiving bore 266 in the center thereof.Intersecting the transverse slot 264 at the bore 266 is a longitudinalchannel 268 sized to accommodate the end of the ring type biasing spring118. The undersurface of the pawl 116 includes an intermediate recess270 defining a bearing surface 272 and a rearward heel portion 274terminating in a pivot 140 adapted to be seated at the junction of thebottom and side defining walls of the recess 110. Extending upwardlyfrom the pivot 140 is an inclined rear wall portion 134.

As will hereinafter be pointed out, the front and rear inclined walls130 and 134 comprise the load bearing surfaces of the pawl members 116and are disposed in substantially parallel relation to each other.

The above described pawl configuration serves to permit the ring typebiasing springs 118 to normally bias the pawls 116 into seatingengagement with the shoulder 252 forming the floor of the recess 110 andin bridging position over the inner channel 112. Such springs 118 alsoserve to maintain the pivot 140 at the apex 142 of the angle formed bythe vertical wall 136 and shoulder 252 of the recess 110 and to thuspermit selective pivotal and radially outward displacement of the frontend portion of the pawls 116 while maintaining said pivot fixed inposition.

As will now be apparent, each of the drive gears 92, 94 and 96 is freelyrotatable on the enlarged hub portion 106 of the pedal drive shaft 32and each of the pawls 116 is normally biased downwardly within thelongitudinal recess 110 by the action of its respective ring typebiasing spring 118. As most clearly shown in FIG. 7A, when a pawl 116 isso biased, it is out of engagement with its drive gear and there is nodriving engagement between the enlarged hub portion 106 of the pedaldrive shaft 32 and the drive gear associated with said pawl. Elevationof the front end 126 of a selected pawl 116 upwardly and out of therecess 110 is effected by longitudinal displacement and selectivepositioning of the elongate leaf spring type actuating member 114 withinthe elongate recess 112 in the pedal drive shaft 32. The selectiveengagement of the angularly shaped terminal end 124 thereof, due to thebiasing action of said leaf spring actuating member 114, with theunderside of a pawl 116, as shown in FIGS. 4 and 7B, overcomes theaction of its ring type biasing spring 118 and pivotally elevates thefront end 126 of the pawl 116 radially outwardly of the recess 110. Dueto the interaction of the outwardly directed biasing action of the camsurface 124 on the leaf spring type actuating member 114 on theunderside of a pawl 116 and the restraining action of the ring spring118 associated therewith, a pawl is rotated about its heel 140 in thecorner 142 of recess 110. Such pivotal pawl displacement places thecrest 262 on the top of the pawl 116 into compressive engagement withdefining surface of the bore 128 of the selected drive gear. Since thepedal drive shaft 32 will normally be rotating in the direction of thearrow in FIGS. 7A and 7B when the bicycle is being pedaled in theforward direction, the so upwardly biased pawl 116 will soon reach oneof the recesses 108 and will be further upwardly displaced therein underthe continued biasing action of the actuating member 114. Upon entry ofthe pawl 116 into a recess 108 and with continued rotation of the pedaldrive shaft in the bicycle advancing direction as indicated by thearrows in FIGS. 7A and 7B, the inclined wall 130 on the front of thepawl will be disposed and maintained in compressive interfacialengagement with the wall 132 of the recess and the rear wall 134 of thepawl will be disposed in compressive interfacial engagement with thewall 136 of the recess 110. When so engaged and positioned, asillustrated in FIG. 7B, a direct driving connection is thus establishedbetween the forwardly rotating enlarged hub portion 106 of the pedaldrive shaft 32 and a selective drive gear, as for example gear 92, andsuch driving connection will be effectively maintained, and/or readilyreestablishable, until the elongate leaf spring type actuating member114 is longitudinally displaced within the channel 112 out of engagementwith the drive pawl 116 for such gear 92.

The sloped upper surface 260 of the drive pawl 116 permits ready advanceof the engaged drive gear relative to the drive shaft 32 as would occurwhen the forward rotative advance of the drive shaft 32 is halted oreven reversed. Such halting of advance or reverse rotation of the pedaldrive shaft 32 effects automatic disengagement of a drivingly engagedpawl from the recesses 108 in the gear bore 128 and its reintroductioninto the recess 110 in the hub 110 without otherwise affecting thecontinued upward biasing of such pawl 116 by the action of the angularlyshaped end 124 of the elongate leaf spring type actuating member 114.Such disengaging and retraction action permits the bike rider to coastwith a temporary disengagement of all driving connection between thepedal drive shaft 32 and the main drive sprocket 52. The above describeddriving connection between an outwardly biased pawl 116 and a recess 108in the bore 128 of the drive gear will automatically be reestablishedwhen pedal drive shaft 32 rotation in the bicycle advancing direction isresumed by the rider.

As described above and as shown in FIGS. 4, 7A and 7B, the pawls 116 areselectively shaped to provide for parallel interfacial engagementbetween pawl surface 130 and sidewall 132 of recess 108 and also betweenpawl surface 134 and sidewall 136 of recess 110 to assure that the pawlsare in compression at all times when a driving engagement exists betweena drive gear and the pedal drive shaft 32.

As will now be apparent, the specifically illustrated and described setof drive and change gears is adapted to provide for three separate speedratios for the main drive sprocket 52. For example, when the leaf springactuating member 114 has been positioned within the longitudinal recess112 in the pedal shaft 32 so that its cam shaped terminal end 124elevates the pawl 116 into driving engagement with a pawl engageablerecess 108 in the bore 128 of drive gear 92, the drive gear 92 will bedirectly driven by the rotation of the pedal drive shaft 32. At thattime, the main drive sprocket 52 will be directly driven by gear 92through its hub 100 and will be advanced at a 1 to 1 ratio with therotation of the pedal drive shaft 32. Under such conditions, the gear 92will also directly drive companion gear 80 which in turn will rotatechange gears 84 and 86 in conjunction therewith. Change gears 84 and 86will directly drive the freely rotatable drive gears 94 and 96, whichare now unconnected to the enlarged hub 106 of pedal drive shaft 32, atspeeds determined by the various gear ratios involved. If, under suchconditions, the leaf spring actuating member 114 is longitudinallydisplaced within recess 112 out of engagement with the above-mentionedpawl 116 for gear 92 and into lifting engagement with the pawl 116associated with drive gear 94, the drive gear 92 will be disengaged fromdriving engagement with the pedal drive shaft 32 by retraction of thedrive pawl 116 therefore into the recess 110 and the pawl 116 underlyinggear 94 will be elevated into driving engagement with the pawlengageable recess 108 in the bore 128 of the drive gear 94. Under suchconditions, the gear 94 will be directly driven by the rotation of thepedal drive shaft 32. In this instance, however, drive gear 94 willdirectly drive companion gear 84 at a speed W₁ rpm, determined by thegear ratios therebetween. Companion gear 84 will drive change gears 86and 80 at the same speed W₁ rpm. Change gear 80, however, will now drivethe now freely rotatable drive gear 92 at a speed W₂ rpm determined bythe gear ratio therebetween and, of course, will thus drive the maindrive sprocket 52 at the same speed W₂ rpm. At the same time, changegear 86 will also drive the freely rotatable drive gear 96 at a speeddetermined by the gear ratio therebetween. As will now be apparent,similar operation will be effected if the gear 96 is drivingly engagedwith the pedal shaft 32.

The specific gear ratios for the drive and change gears may be suitablypreselected to accommodate the preferences of the bicycle manufacturer.

It should also be noted, that under the above described action, at leastone drive gear will always be drivingly engaged or biased for drivingengagement with the pedal drive shaft 32. That is, the angularly shapedend 124 of the leaf spring actuating member 114 will always be inoperative biasing engagement with at least one of the drive pawls 116.

Controlled longitudinal displacement of the elongate leaf springactuating member 114 within the elongate channel 112 in the pedal driveshaft 32 to effect the selective driving engagement of the drive gears92, 94 and 96 to the pedal drive shaft 32 through the above describedselective elevation of the pawls 116, is effected by a drive pedalresponsive shifting mechanism disposed within the pedal hub 30 thatconventionally forms an integral part of the standard bicycle frame 14.To the above end, the pedal drive shaft 32 is journalled within thegenerally cylindrical shell 148 of the pedal hub 30 by spaced ballbearings 150, 152. Disposed between the ball bearings 150, 152 andwithin the shell 148 is a fixed cylindrical sleeve 154. In theillustrated embodiment, the interior surface of the sleeve 154 is ofcontinuous character except for a rectangularly shaped aperture 146therein. Disposed within the aperture 146 is a selectively displaceablerectangularly shaped sector-like member 156. The sector-like member 156is pivotally mounted, as at 158, and serves as a hinged shift controlmember. Such control member 156 is normally biased, as by a ring typebiasing spring 160, into its advanced or closed position as shown at 162in FIG. 5. When so normally biased, its inner surface is disposedsubstantially flush with the remainder of the inner surface of the fixedsleeve 154.

As shown in FIGS. 5 and 9, the control member 156 generally comprises anarcuate and pivotally displaceable flap like member having a pair ofspaced inwardly directed and spaced pin members 166 and 168 (for theillustrated three drive gear transmission) mounted on the free end 164thereof. As will later become apparent, the pins 166 and 168 are spacedapart a distance substantially equal to the spacing of the center linesof the drive gears 92, 94 and 96. The thickness of the control member156 is progressively decreased from its pivotal mounting 158 to its freeend 164 in order to permit radially outward pivotal displacement of saidfree end 164 against the restraining action of the biasing spring 160,as will be hereinafter described.

The portion of the pedal drive shaft 32 disposed within the fixed sleeve154 is flatted as at 176, 178. A longitudinally displaceable shiftcollar member 180 having a cylindrical external surface is mounted onthe flatted portion of the pedal drive shaft so as to be slidablydisplaceable therealong and conjointly rotatably displaceable therewith.The collar member 180 overlies the terminal end of the longitudinalchannel 112 containing the elongate leaf spring actuating member 114. Asclearly shown in FIGS. 2 and 3, the leaf spring actuating member 114suitably comprises an elongate strip of spring steel or the like havingone terminal end 184 thereof secured to the collar member 180 and anintermediate body portion 186 disposed within the channel 112 that is ofa length adapted to place the angularly shaped terminal end portion 124thereof in selective operative biasing engagement with the underside ofthe pawls 116 for the drive gears 92, 94 and 96 in accord with theselective positioning of the collar member 180 longitudinally of theflatted surface 176, 178 of the pedal drive shaft 32. As shown in FIG.6, selective positioning of the collar member 180 at three discretelocations longitudinally of the pedal drive shaft 32 is assisted byspring loaded detent means in the form of a pair of ball detents 190,192 urged by a spring disposed within a bore 202 in shaft 32 into one ofthree recesses 196, 198 and 200 located on the inner surface of thecollar member 180, so as to selectively position the angularly shapedterminal end 124 of actuating member 114 in selective operativeengagement with each of the pawls 116 for upwardly displacing the sameinto driving engagement with one of the drive gears 92, 94 and 96 asabove described. Positive action of the detent system to displace thecollar 180 from either of its limiting positions, as defined by recesses196 and 200, to its intermediate position, as defined by recess 198, iseffected by the sloping surfaces 172 and 174 that form the guide forball detent 192.

Referring now to FIGS. 5, 10A and 10B, a pair of angularly disposedcamming ridges 206 and 208 are mounted in diametrically opposed relationon the exterior cylindrical surface of the slidable shift collar 180.Each of the camming ridges include one perpendicular cam surface 210 andone slanted or inclined cam surface 212. Such are operatively related tothe pins 166 and 168 on the pivotally mounted shift control member 156so that engagement of the perpendicular cam surfaces 210 with such pinmembers 166 and 168 will effect axial displacement of the collar member180 relative to the pedal drive shaft 32 as the latter is rotated inreverse direction and that engagement of the inclined cam surfaces 212with the pin members 166 and 168 will effect an outward pivotaldisplacement of control member 156 and no displacement of the collar 180relative to the pedal drive shaft 32 when the latter is being rotated inthe forward direction.

As shown in FIG. 10A, rotation of the pedal drive shaft 32 in the normalor bicycle driving direction, as indicated by the arrow 216, causes theslanted or inclined cam surfaces 212 of the camming ridges 206 and 208to repetitively engage either one of the pin members 166 and 168 on thehinged control member 156. Each such engagement causes the engaged pinmember 166 or 168 to ride up the inclined cam surface 212 and outwardlydisplace the free end 164 of the hinged control member 156 into aretracted position against the inward biasing action of the springmember 160, which functions to return the hinged control member 156 intoits advanced position in coplanar relation with the interior surface ofthe sleeve 154 once the camming ridge has been advanced past the pins166, 168. Thus, during the normal or forward rotation of the pedal driveshaft 32, the collar member 180 rotates in conjunction therewith withoutany lineal or axial displacement of the collar 180 axially of the driveshaft 32.

In contrast thereto and as shown in FIG. 10B, rotative displacement ofthe pedal drive shaft 32 and collar member 180 in the reverse direction,as illustrated by the arrow 214, will, at one particular and readilylocatable point of pedal positioning, effect engagement of theperpendicular surface 210 of camming ridge 206 with the sidewall of oneof the pins 166 or 168. As will now be also apparent, the perpendicularsurface 210 of the second camming ridge 208 will engage the sidewall ofone of the pins 166 or 168 at a second particular and readily locatablepoint of pedal positioning that is 180° removed from the above describedfirst point of engagement. Under such engagement, the hinged controlmember will not be displaced from its advanced position coplanar withthe interior surface of the sleeve 154 but rather will remain in itsadvanced position.

Referring now also to FIGS. 11A through 11D by way of example, which isan unfolded plan view of the cylindrical surface of the shift collar180, the upshifting and downshifting action effected throughinterengagement of the perpendicular cam surfaces 210 and the pins 166and 168 on the control member 156 will be described. In FIG. 11A, theperpendicular surface 210 of the camming ridge 206 is disposed inabutting engagement with the pin 166 as would be obtained, for example,by location of the left pedal crank 36 and left drive pedal 40 at afirst predetermined point in their path of rotation. When so positioned,the leaf spring actuating member 114 will be at its limiting advancedposition in engagement with the drive pawl 116 for the outermost drivegear 96 and with such gear disposed in driving engagement with the pedaldrive shaft 32. When the components are so located, continued reverserotational displacement of the collar member 180 as indicated by thearrow 214 through a limited arc, as determined by the length and pitchof the camming ridge 206, will effect a concommitant lineal displacementof the collar 180 axially of the pedal drive shaft 32 as indicated bythe arrow 218 and to the positioning illustrated in FIG. 11B as thecamming ridge 206 is displaced past the pin 166. Such positivedisplacement of the collar 180 will effect an accompanying displacementof the leaf spring actuating member 114 from its advanced position to anintermediate position in engagement with the drive pawl 116 for theintermediate drive gear 94 and with the latter intermediate gear 94 nowbeing disposed in driving engagement with the pedal drive shaft 32 uponresumption of forward rotational displacement of the latter.

As will be apparent from a comparison of FIGS. 11A, 11B and 11 C, thedescribed collar displacement will selectively locate the perpendicularsurface 210 of the camming ridge 206 in position to operatively engagethe second pin 168 on the control member 156 whenever the left pedalcrank 36 and left drive pedal 40 are again disposed at the above notedfirst predetermined point in their path of rotation, as illustrated inFIG. 11C. When the components are so located, continued reverserotational displacement of the collar member 180, as indicated by thearrow 214, through a limited arc, as determined by the length and pitchof the camming ridge 206, will effect a concommitant lineal displacementof the collar 180 axially of the pedal drive shaft 32 as indicated bythe arrow 218 and to the positioning illustrated in FIG. 11D as thecamming ridge is displaced past the pin 168. Such positive displacementof the collar 180 will effect an accompanying displacement of the leafspring actuating member 114 from its intermediate position, as abovedescribed, to its fully retracted position in engagement with the drivepawl for the drive gear 92 and with the latter gear 92 now beingdisposed in driving engagement with the pedal drive shaft 32 uponresumption of forward rotational displacement of the latter.

As also shown in FIG. 11D, such displacement of the collar 180 hasselectively located the diametrically disposed second camming ridge 208so that its perpendicular surface 210 is positioned to operativelyengage the second pin 168 (shown dotted) whenever the left pedal crank36 and left drive pedal 40 are disposed at a second predetermined point,180° removed from the above described first point, in their path ofrotation. When the components are so located, continued reverserotational displacement of the collar member 180, as indicated by thearrow 214, through a limited arc as determined by the length and pitchof the camming ridge 208, will effect a concommitant lineal displacementof the collar 180 axially of the pedal drive shaft 32 as indicated bythe arrow 220 and to the positioning illustrated in FIGS. 11C and 11B,as the camming ridge 208 is displaced past the pin 168. Such positivedisplacement of the collar 180 will effect an accompanying displacementof the leaf spring actuating member 114 from its retracted position intoits intermediate position in engagement with the drive pawl 116 for theintermediate drive gear 94 and with the latter intermediate gear nowbeing disposed in driving engagement with the pedal drive shaft uponresumption of the forward rotational displacement of the latter.

As will be apparent from a comparison of FIGS. 11D, 11C and 11B, theabove described collar displacement will selectively locate theperpendicular surface 210 of the camming ridge 208 in position tooperatively engage the pin 166 on the control member 156 whenever theleft pedal crank 36 and left drive pedal 40 are again disposed at theabove noted second predetermined point in their path of rotation. Aswill also be apparent from FIGS. 11B and 11C, when the collar 180 is inits intermedaite position both the camming ridges 206 and 208 areselectively located for pin engagement to permit either upshifting ordownshifting at the option of the rider.

When the perpendicular surface 210 of the camming ridge 208 ispositioned relative to the pin 166 as shown in FIG. 11B, continuedreverse rotational displacement of the collar member 180 as indicated bythe arrow 214, through the limited arc determined by the length andpitch of the ridge 208 will effect a concommitant lineal displacement ofthe collar 180 axially of the pedal drive shaft 32 in the directionindicated by the arrow 220 and to the position illustrated in FIG. 11A.In the manner described above, such collar displacement will effect anaccompanying displacement of the actuating member 114 from itsintermediate to its fully advanced position wherein the drive gear 96 isdisposed in driving engagement with the pedal shaft 32 upon resumptionof forward rotational displacement of the latter.

In the above described construction, shifting is limited to collardisplacement intermediate the above described advanced and retractedpositions. Thus, once the limit of upshifting or downshifting has beeneffected, no further undirectional shifting can be effected since theoperative camming ridges will be positioned out of operative range ofthe pins.

As will now be apparent, the diametrically separated location andopposed positioning of the camming ridges 206 and 208 effectivelylocates two predeterminable positions for the right and left pedals 38and 40, at which reverse rotation through a small arc as determined bythe length and pitch of the camming ridges 206 and 208 will effect"upshifting" or "downshifting" of the transmission. For example,upshifting may be conveniently effected by limited reverse rotation, forexample, through about 30° of reverse movement of the right pedal 38when such pedal is in its lowermost position and downshifting effectedby similar limited reverse rotation of the left pedal 40 when such pedalis in its lowermost position.

As above described, a predetermined minimum amount of reverse rotativedisplacement of the pedal drive shaft 32 is required, at either of thetwo defined locations to effect a shifting of the gears. At the timethat such minimum degree of reverse rotative displacement of the pedaldrive shaft 32 has been effected, the action of the spring loaded indentball 190 will complete the displacement of the collar 180 necessary toeffect the desired gear shift through transfer of the indent ball 190 tothe adjacent locking recess. If however, reverse rotation is initiatedat the proper location but the minimum required amount of reversedisplacement is not effected by the rider, the action of the springbiased indent ball 192 under the action of the sloping seat surfaces 172or 174, will serve to relocate the collar 180 in its intermediateposition, where the indent ball 190 is seated in recess 198.

As will now be apparent to those skilled in this art, while theillustrated construction is presently preferred, axial displacement ofthe collar 180 in response to reverse rotation of the drive pedal shaftcould be similarly effected by mounting the camming ridges on the sleeve154 and locating the pins 166 and 168 on the collar 180. For example, apair of shift control members disposed 180° apart could have the cammingridges mounted thereon and with the pin members 166 and 168 mounted onthe collar. Likewise, the camming ridges could be integral with thesleeve 154 and the pins 166 and 168 mounted on a pivotally displaceablecontrol member forming a part of the collar 180.

The foregoing pedal responsive multi-speed transmission providesenhanced safety for the bicycle rider in that it does not requirerelease of the handle bars by the operator or diversion of vision fromthe path of travel during shifting operations entirely apart from arapidity of operation that minimizes the time required to change speeds.The described system is also essentially fail-safe in that if any pawlmember biasing spring fails and permits its pawl 116 to become drivinglyengaged with its related drive gear, then such gear will operativelydrive the bicycle unless another and deliberately engaged drive gearhappens to be one that would drive the bicycle at a higher speed. Thus,if through biasing spring failure, more than one drive gear getsdrivingly engaged with the rotating pedal drive shaft 32, the drive gearthat will produce the highest speed will do the driving and the othergear will be overridden due to the sloping upper surface of the drivepawls 116.

Having thus described my invention, I claim:
 1. A pedal displacement actuatable multi-speed transmission for bicycles, comprisinga pedal shaft rotatably displaceable within the pedal shaft hub of a bicycle frame, a plurality of drive gears rotatably mounted on said pedal shaft, means for connecting each of said drive gears into selective driving engagement with said pedal shaft, collar means mounted on said pedal shaft for rotation in conjunction therewith and permitted longitudinal displacement therealong, means engageable with said collar means and responsive to a predetermined arc of reverse rotative displacement of said pedal shaft for displacing said collar means longitudinally thereof, and means responsive to the positional location of said collar means longitudinally of said pedal shaft for effecting the selected connection of each of said drive gears into driving engagement with said pedal shaft.
 2. A bicycle transmission as set forth in claim 1 includinga pedal drive sprocket directly driven by one of said drive gears and drive chain means driven by said sprocket connectable to the rear drive wheel of said bicycle.
 3. A bicycle transmission as set forth in claim 1 wherein said means connecting each of said drive gears into driving engagement with said pedal shaft comprisespawl means effectively subject to stress only during forward rotative displacement of said pedal shaft.
 4. A bicycle transmission as set forth in claim 3 wherein said stress is compressive.
 5. A bicycle transmission as set forth in claim 1 in combination with a multi-speed transmission associated with the hub of the rear wheel of a bicycle and interconnected therewith by a drive chain.
 6. A bicycle transmission as set forth in claim 3 wherein said means for effecting the selected connection of said drive gears into driving engagement with said pedal shaft comprises an elongate member having one terminal end thereof secured to said collar member and the other end thereof normally biased into lifting engagement with the underside of said pawl means.
 7. A bicycle transmission as set forth in claim 1, wherein said means for connecting the drive gears into selective driving engagement with said pedal shaft and said means for effecting the selected connection of said drive gears into driving engagement with said pedal shaft are substantially stress free during displacement of said collar member.
 8. A bicycle transmission as set forth in claim 1 wherein said means for connecting each of said drive gears into driving engagement with said pedal shaft comprises compressively stressable displacement pawl means.
 9. A pedal displacement actuable multi-speed transmission for bicycles, comprisinga pedal shaft rotatably displaceable within the pedal shaft hub of a bicycle frame, a plurality of drive gears rotatably mounted on said pedal shaft, displaceable pawl means for connecting each of said drive gears into selective driving engagement with said pedal shaft, a collar member mounted on said pedal shaft for rotation in conjunction therewith and permitted longitudinal displacement therealong, camming means said collar member, a pivotally mounted shift control member displaceable radially of said pedal shaft disposed in spaced relation with said collar member, means mounted on said shift control member and operatively engageable with said camming means in response to a predetermined arc of reverse rotative displacement of said pedal shaft for displacing said collar member longitudinally thereof, and means responsive to the positional location of said collar member longitudinally of said pedal shaft for effecting the selected displacement of said pawl means and connection of each of said drive gears into driving engagement with said pedal shaft.
 10. A bicycle transmission as set forth in claim 9 wherein said means for connecting the drive gears into selective driving connection with the pedal shaft comprises pawl members individually displaceable in accord with the position of said collar member axially of said pedal shaft.
 11. A bicycle transmission as set forth in claim 9 wherein said last mentioned means comprises elongate leaf spring actuating means.
 12. In a multi-speed transmission,a rotatably displaceable drive shaft, a plurality of drive gears rotatably mounted on said drive shaft, means for connecting each of said drive gears into selective driving engagement with said drive shaft, collar means mounted on said drive shaft for permitted longitudinal displacement therealong, means responsive to a predetermined arc of reverse rotative displacement of said drive shaft for displacing said collar means longitudinally thereof, and means responsive to the positional location of said collar means longitudinally of said drive shaft for effecting the selected connection of each of said drive gears into driving engagement with said drive shaft.
 13. The combination as set forth in claim 12 wherein said means for connecting each of said drive gears into driving engagement with said drive shaft comprises,pawl members normally biased in retracted position within the perimeter of said drive shaft and displaceable into elevated driving engagement with said drive gears to selectively rotate the latter in conjunction with the rotation of said drive shaft.
 14. The combination as set forth in claim 13 wherein said pawl members displaced in driving engagement with said drive shaft are subject to compressive stress.
 15. The combination as set forth in claim 13 wherein said pawls are pivotally displaceable into elevated position and are drivingly engageable with said drive gears in selective response to unidirectional rotation of said drive shaft. 